The present invention relates to a mechanical actuating device for a spot-type disc brake comprising a caliper embracing a brake disc inwardly or outwardly, at least one leg of which includes an actuating spindle extending axially therein and an actuating nut cooperating therewith, the actuating spindle and actuating nut acting on the adjacent brake shoe upon a relative rotation with respect to each other by means of an actuating means biased to its initial position and an adjusting device for an automatic adjustment of the appropriate clearance between brake shoe and brake disc after a braking operation. The present invention relates in particular to a special construction of a floating caliper brake, i.e., the so-called fist-type caliper brake, in which one single bridge encompasses the brake disc in a fist-like manner.
Known spot-type floating-caliper disc brakes (German Patents DE-AS No. 1,575,996 and DE-AS No. 1,257,603) are always equipped with special adjusting spindles or special adjusting threads for performing the automatic adjustment in the case of the brake pads being worn.